Auxiliary drive for a training device

ABSTRACT

An auxiliary drive for a training device, comprising a first force measuring device, a control device, and a drive unit, wherein the control device determines a target force F S,max , the first force measuring device determines an actual force F S  which is applied to a main traction means and which is caused by an acceleration of a movable mass connected to the main traction means. The first force measuring device also transmits the determined actual force F S  to the control device, and the control device also compares the actual force F S  with the target force F S,max  and controls the drive unit such that, if the actual force F S  exceeds the target force F S,max , an auxiliary force F Z  having a component that offers resistance to a gravitational acceleration acts on the movable mass by connection of the drive unit to the movable mass.

RELATED APPLICATION INFORMATION

This patent is a Continuation-in-Part of International PCT Patent Application No. PCT/EP2019/083537, filed Dec. 3, 2019 entitled, “AUXILIARY DRIVE FOR A TRAINING DEVICE”, which claims priority to German Patent Application No. 10 2018 220 953.7, filed Dec. 4, 2018 entitled, “AUXILIARY DRIVE FOR A TRAINING DEVICE”, all of which are incorporated herein by reference in their entirety.

NOTICE OF COPYRIGHTS AND TRADE DRESS

A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by anyone of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever.

BACKGROUND

The invention relates to an auxiliary drive for a training device, said auxiliary drive comprising a first force measuring device, a control device, and a drive unit, and a system comprising the training device and the auxiliary drive for the training device.

By means of the auxiliary drive according to the invention for the training device, it is possible both for an existing training device, in particular a strength training device, to be retrofitted in a relatively simple manner and a new training device to be equipped accordingly during assembly. The deinstallation of the auxiliary drive according to the invention is also possible in a non-destructive manner, so that it can then be used subsequently in another training device, for example. The quasi-modular structure of a system including the auxiliary drive and the strength training device also offers increased flexibility in production to a manufacturer. Furthermore, of course, the auxiliary drive may be manufactured and offered completely separately.

By way of example, strength training devices are described in which the total movable mass may essentially consist of a plurality of mass plates vertically arranged one above the other. By way of example, these mass plates are connected via a driver bar and a plug pin, which are then moved along accordingly and which define the total movable mass accordingly.

Hence, assuming a certain/known acceleration, the maximum training load is defined by setting the total movable mass, for which purpose the pin is arranged accordingly. As a rule, when the person exercising applies a force, the acceleration of the total movable mass thereof is directed against the acceleration of gravity.

Common strength training devices configured purely mechanically have the disadvantage that the training load can only be changed at discrete intervals, namely according to the mass of the individual weight plate (for example 5 kg each). Any such change must be made actively, usually by replugging the pin, so that it is virtually impossible for a different load to be applied in the concentric phase and in the eccentric phase. A continuous adaptation to the cardiovascular values of the person exercising is also hardly possible. Active training devices (fully electric strength training devices) that can generate a dynamic load purely electrically, also offer the above-mentioned training options, but are much more expensive both to purchase and to maintain and must be provided with complex safety measures in order to exclude overloading the person exercising when the device is malfunctioning. The power consumption of such active training devices is also significantly higher than that of the auxiliary drive according to the invention.

Therefore, the object of the invention is to provide an auxiliary drive for a training device and a system comprising the training device and the auxiliary drive for the training device in order to provide a safe and optimized training load.

As described above, assuming a set/known acceleration, the maximum training load is well defined by defining the total movable mass. If the person exercising now intentionally applies a force, the resulting acceleration of the total movable mass is directed against the acceleration of gravity.

This serves to provide safety in two ways. On the one hand, a secure mechanical connection between the mass plates and the rest of the movable mechanical parts of the training device can be established in a relatively simple manner. On the other hand, the total movable mass is well defined, namely essentially by the mass plates connected to one another by means of the plug pin. The maximum training load defined by setting the total moveable mass—which requires a determined/known acceleration—cannot be exceeded unintentionally or unexpectedly, since, due to the total moveable mass per se, the person exercising always has to apply a maximum force corresponding to the product of the total moveable mass and the desired acceleration against the acceleration of gravity. From the point of view of and with respect to the effect on the person exercising, the auxiliary drive according to the invention for the training device can therefore invariably only apparently reduce the total movable mass and the load resulting therefrom, but never actually increase it.

The auxiliary drive for training devices according to the invention maintains these two essential safety features, in particular the maximum possible (desired) training load well defined by the total movable mass. The configuration of the auxiliary drive for training devices according to the invention offers the particular advantage that the maximum possible training load, which is well-defined by the total movable mass, can be reached, but can never be exceeded unintentionally. For this purpose, the auxiliary drive according to the invention only acts on the total movable mass in such a way that at least one component of the force resulting from the action acts against the acceleration of gravity, that is, against the acceleration due to gravity or acceleration of fall.

This is also one of the main advantages of the present invention over active training devices (fully electric strength training devices) which can generate a dynamic load purely electrically. For such devices, a very high level of safety precautions is necessary in order to avoid excessive loads or even possible injuries in the event of a malfunction. In principle, active training devices (fully electric strength training devices) have a very high cost, both in terms of acquisition and maintenance.

By means of the auxiliary drive for the training device according to the invention, the force to be actually applied, and thus the load, may be adjusted continuously while the exercise is being carried out, while the set maximum training load is reliably constrained. In the simplest case, a maximum load which is incremented as finely as needed and which can at most correspond to the maximum training load predetermined by the total movable mass can be set. Such a maximum load can also be adjusted while carrying out an exercise. A purely temporal adjustment or also an adjustment related to a predetermined cycle, which can also take into account cardiovascular values of the person exercising, is conceivable here.

Another very important advantage of the auxiliary drive according to the invention is that it can generate a so-called “eccentric overload”. It is called an eccentric overload in a movement phase when the muscle is stretched (eccentric contraction) and experiences a higher load than the load it was previously exposed to in the concentric movement phase that shortens the muscle (active muscle shortening; concentric contraction) or the load when the length remains constant against a counterforce (isometric contraction). In a typical weight stack strength training device, the eccentric contraction and the concentric contraction would ideally be the same, but due to the contribution of friction losses, the force in the concentric phase is always slightly higher than in the eccentric phase. However, since the muscles could be loaded up to about 30% more in the eccentric contraction, a corresponding training stimulus on the muscles is lost, which in turn only triggers reduced muscle growth.

Due to the continuous load control during a movement enabled by the auxiliary drive according to the invention, the force curves can also be optimally matched to the leverage ratios of an exercise and a person exercising. It is also apparent when a person exercising should adjust the load. This also allows for automated training load adjustments, for example.

The auxiliary drive according to the invention as a conversion kit may be configured such that only additional elements are installed, but no mechanical changes have to be made to the existing mechanical parts or to a cover or to a force-transmitting part of the existing strength training device. There is also no need to deinstall any pull ropes or weight plates, and there is no need for specialist personnel trained in the use of electrics or electronics to put the device into operation and monitor it during normal operation. Due to the type of mounting and the basic functionality of the auxiliary drive according to the invention, as described above, the person exercising cannot experience higher mechanical loads than the settable maximum training load, the range of which is already specified by the manufacturer via the weight plates. In this way, problems with product liability or outstanding guarantee claims can also be avoided.

It is also advantageous that the mechanics of the auxiliary drive according to the invention may be formed from a number of common machine elements, allowing for the costs for acquisition, operation, maintenance, servicing and replacement, among other things, to be reduced.

To achieve the object, an auxiliary drive for a training device having the features mentioned in claim 1 is proposed.

Such an auxiliary drive for the training device may comprise at least one first force measuring device, at least one control device and at least one drive unit. The control device may determine a target force, F_(S,max), which is to correspond to the maximum load on the person exercising. This target force, F_(S,max), is variable both with respect to time and additionally determined variables; Such a variation may be continuous, almost discrete and/or cyclical. The target force, F_(S,max), may be determined, for example, as a function of a direction of movement, a speed of movement, a change in the speed of movement, a value of the cardiovascular system of the person exercising or a combination thereof; a large number of physiological values that can be included in the calculation of the target force, F_(S,max), are conceivable. The first force measuring device may determine an actual force, F_(S), which can be applied to a main traction means of the training device, on which the person exercising acts, and which may essentially be caused by an acceleration of a movable mass connected to the main traction means. Such a main traction means may be, for example, a rope or a belt, that is, a machine element suitable for transmitting a tractive force. This acceleration of the movable mass may be both the always-acting acceleration of gravity or acceleration of fall—that is the essentially constant acceleration due to gravity—as well as an additional dynamic acceleration induced by the person exercising. The actual force, F_(S), determined at the main traction means may be transmitted from the first force measuring device to the control device. The control device may then compare the transmitted actual force, F_(S), with the target force, F_(S,max), and—if the actual force, F_(S), exceeds the target force, F_(S,max)—the control device may control the drive unit in such a way that, via a connection between the drive unit and the movable mass, an auxiliary force, F_(Z), having a component opposed to the acceleration of gravity can act on the movable mass.

Since the control device only controls the drive unit when the actual force, F_(S), measured at the main traction means exceeds the target force, F_(S,max), the load on the person exercising can never be greater than the load that results from the movable mass and the total acceleration acting thereon. If the person exercising does not apply a load that actually accelerates the movable mass against the acceleration of gravity, the acceleration of gravity acts as the maximum acceleration of the movable mass. Therefore, if at least one component of the auxiliary force, F_(Z), acts against the acceleration of gravity, it is ensured that the person exercising can never unexpectedly experience a potentially dangerous high load. This protection may also be further increased by deliberately restricting the auxiliary force either absolutely or relative to the movable mass; for example to a maximum of 150 N or 20% of the movable mass. Since the auxiliary power, F_(Z), can be limited with a fully functioning auxiliary drive for the training device, even if a complete system failure is assumed, the additional load cannot exceed the limited auxiliary power, F_(Z), removed and thus can only amount to a maximum of 20% of the movable mass, for example. In addition to providing increased safety, an increase in power consumption may also be avoided.

Moreover, such an auxiliary drive for the training device may also provide an emergency braking function for the drive unit. In the event of a power failure or another malfunction, a hardware-implemented safety emergency stop function may be integrated, which then short-circuits the windings of an electric motor of the drive unit. As a result, the movable mass can be braked with a maximum torque of the electric motor in the event of a fault or in the event of disproportionately deviating measured values, for example exceeding a limit value.

The dependent claims relate to advantageous embodiments and further developments of the invention.

In the auxiliary drive, the control device may compare the transmitted actual force, F_(S), with the target force, F_(S,max), and, if the actual force, F_(S), exceeds the target force, F_(S,max), the control device may control the drive unit in such a way that the auxiliary force, F_(Z), reduces the determined actual force, F_(S), applied to the main traction means via the connection of the drive unit to the movable mass. This makes it possible to ensure that the actual force applied to the main traction means, F_(S), has actually been reduced by the auxiliary force, F_(Z), so that safety can be increased.

In the auxiliary drive, the control device may compare the transmitted actual force, F_(S), with the target force, F_(S,max), and, if the actual force, F_(S), exceeds the target force, F_(S,max), the control device may control the drive unit in such a way that, via the connection of the drive unit to the movable mass, the auxiliary force, F_(Z), reduces the determined actual force, F_(S), applied to the main traction means substantially to the target force, F_(S,max). In this way it can be ensured in a verifiable manner that the force to be applied by the person exercising now essentially corresponds to the target force, F_(S,max), for example apart from existing friction losses. If the target force, F_(S,max), changes, the actual force, F_(S), changes accordingly due to the control since the auxiliary force, F_(Z), is permanently adjusted. While retaining all of the positive safety features described above, a load that can be adjusted and optimized almost at will can be generated for the person exercising.

The auxiliary drive may additionally comprise a movement sensor which can be configured to determine a direction of movement of the movable mass and to transmit it to the control device, and the control device may further be configured to additionally determine the target force, F_(S,max), as a function of the direction of movement of the movable mass. Thereby, for example, the “eccentric overload” described above can be generated, allowing for an improved muscle formation can be achieved since the load to be exerted by the person exercising can be adapted to the current direction of movement in an advantageous manner.

The movement sensor of the auxiliary drive may further be configured to determine an absolute or relative position of the movable mass and/or its first and/or second time derivative, or a correspondingly proportional variable, and to transmit it to the control device, and the control device may also be configured to determine the target force, F_(S,max), also as a function of the position of the movable mass and/or its first and/or its second time derivative. This allows for an even finer adjustment of the target force, F_(S,max), to relevant parameters, so that the training effect can be increased on the basis of the improved and, in particular, refined sequences.

Advantageously, the movement sensor may be integrated into the drive unit, whereby both a particularly space-saving design and a special protection against possible external damage can be ensured. Furthermore, the integrity of the measurement may be increased if the movement sensor carries out the measurement directly in the drive unit, so that no other machine elements are involved that could distort the measurement.

Furthermore, the first force measuring device of the auxiliary drive may be configured to determine a tension of the main traction means in order to determine the actual force, F_(S). In principle, if the tension is known, the actual force, F_(S), applied can be inferred very accurately, also increasing the accuracy of the control resulting from the comparison with the target force, F_(S,max).

The first force measuring device may advantageously be configured in such a way that the tension of the main traction means is determined using a deflection. This represents a particularly reliable method of determining the tension and therefore determining the actual force, F_(S), applied, in turn increasing the reliability of the control resulting from the comparison with the target force, F_(S,max).

In addition, the first force measuring device may be configured to determine an elongation of the main traction means in order to determine the actual force, F_(S). The applied actual force, F_(S), may also be inferred very accurately from an elongation.

Since, in the linear-elastic range (proportional range, “Hooke's straight line”), the elongation is proportional to the tensile stress and Hooke's law therefore applies, both types of determination of the actual force, F_(S), may be carried out either alternatively or in parallel. If there are two measured values of the actual force, F_(S), determined in different ways, they can be compared with one another in a suitable manner, whereby the integrity of the measurement can be increased further. An assessment of the suitability of the measurement method with regard to the speed of the change in the measured values or the dynamics in general is also conceivable.

The first force measuring device may advantageously comprise a strain gauge and/or a magnetostrictive sensor operating according to the principle of magnetostriction. Both strain gauges and magnetostrictive sensors are available from common suppliers in a wide variety of embodiments well adapted to respective needs, also allowing for cost reductions. In addition, strain gauges are in particular very space-saving and can also be easily placed in places difficult to access.

Furthermore, the first force measuring device may be configured to determine the actual force, F_(S), by comprising a weighing device that may be configured to determine the mass of the movable mass and by further comprising an acceleration sensor that may be configured to determine a second change over time in a position of the movable mass. Given knowledge of the accelerated mass and knowledge of the corresponding acceleration, the actual force, F_(S), can be determined directly from Newton's second law by simple multiplication. For this purpose, the weighing device must, for example, at a point at which it can be recognized that the movable mass rests, measure a difference between a weight force for the case that the movable mass only rests due to the influence of acceleration of gravity and for the case that the movable mass does not rest. As already described above, several options of determining the actual force, F_(S), can be carried out both alternatively and in parallel. If two or more measured values of the actual force, F_(S), determined in different ways are available, they can be compared with one another in a suitable manner, whereby the integrity of the measurement can be further increased. In general, the present invention regards it as extremely advantageous if—quite generally—determined variables are determined in different ways and/or multiple times; in particular, the sensor data fusion can be used for this purpose. As mentioned above, the dynamics of the underlying movement may be of importance in the sensor data fusion, as may be the dynamics of the determined values themselves.

Advantageously, the acceleration sensor may be a movement sensor that may be configured to determine the absolute or relative position of the movable mass and the first and second time derivative thereof, or a quantity correspondingly proportional thereto. It is both conceivable that the movement sensor described above is employed in the configuration described here and that an additional movement sensor is employed, the data of which may then be used in addition to those of the existing movement sensor and also to determine further measured values therefrom, in particular after the sensor data fusion has taken place.

In the auxiliary drive, the connection of the drive unit to the movable mass may further act at a first point of the main traction means which is closer to the movable mass than a second point of the main traction means, at which the first force measuring device determines the actual force, F_(S). This ensures that, in the course of the force flow within the main traction means, there can be no distortion of the actual force, F_(S), that is determined by the first force measuring device, is applied to the main traction means of the training device and is essentially to be applied by the person exercising. When the drive unit acts, according to the invention, at the first point of the main traction means, a particularly compact design of the auxiliary drive can be obtained.

In addition, the drive unit may comprise a generator, making it possible, especially in the case of the eccentric movement, that not only no energy is consumed, but energy can even be recuperated, since the generator, for example, provides the braking torque required to generate the appropriate auxiliary force, F_(Z). Since the energy consumption may be reduced in this way, any existing batteries/accumulators may also be smaller and cheaper.

Advantageously, the auxiliary drive may additionally comprise a second force measuring device configured to determine the auxiliary force, F_(Z), acting on the movable mass and/or to determine the work actually performed by the drive unit. Thereby, the control of the drive unit may be checked, the precision of the control can be increased, and the error detection can be improved. An oscillation may also be prevented better in areas in which it might unintentionally be caused by the control. Again, the second force measuring device may be integrated into the drive unit, allowing for a compact, protected design, increasing the integrity of the measurement and allowing for a comparatively simple force-displacement determination. The second force measuring device, like the first force measuring device, may also comprise a magnetostrictive sensor.

Furthermore, the auxiliary drive may additionally comprise an operating unit that may be configured to transmit data, from which the control device may additionally determine the target force, F_(S,max), to the control device. A large number of configurations are conceivable here. In principle, the operating unit may be configured to specify the target force, F_(S,max), and in particular also the curve or change thereof. For example, it is possible to choose from a number of different training programs from which the respectively valid target force, F_(S,max), is then determined. Here, a comparatively simple control device that, in addition to the curves of the target force, F_(S,max), received from the operating unit, does not, or does only to a small extent, perform further calculations to determine the target force, F_(S,max), may also be used.

In addition, the control device may further be configured to transmit data to the operating unit and/or to an IT infrastructure and to receive data from the IT infrastructure. The operating unit may also be configured to receive data from an external measuring unit and/or to receive/transmit data from/to the IT infrastructure. This makes it possible, for example, to show the person exercising how to best follow target curves. In addition, results may be transmitted to the operating unit in order to ensure that a selected target is checked. The data may also be transferred to the IT infrastructure, such as a computer or a cloud, for analysis and evaluation. In particular, the development of a person exercising over time may thus be represented and monitored well, and useful adjustments can be made if necessary. Advantageously, statically or dynamically determined quantities of the person exercising can be transmitted via the operating unit, either by input or by forwarding data, to the control device, or the corresponding calculations can be carried out in the operating unit itself. In addition to, for example, the size and weight of the person exercising, cardiovascular values suitable for determining a corresponding training plan are also conceivable. The specification for the target force curves, F_(S,max), ultimately generated may also originate from a (possibly second) IT infrastructure, such as a computer or a cloud. However, they may also be generated in the operating unit itself or in the control device. The adjustment of the target force, F_(S,max), may also proceed continuously: for example, the IT infrastructure may receive the determined cardiovascular values from the operating unit, along with the data that the control device transmits to the operating unit. The IT infrastructure may then, in turn, make a corresponding adjustment to the target force, F_(S,max), and transmit it to the control device via the operating unit. Restrictions to a single specific structure are therefore not necessary.

The fundamental redundancy of determining the target force, F_(S,max), may be considered a particular advantage since different units may be particularly suitable depending on the (current) data availability and computing power.

Advantageously, the auxiliary drive may further comprise an auxiliary pull rope directly or indirectly connected to both the drive unit and the movable mass, thus establishing the connection of the drive unit to the movable mass. The direct connection may be regarded as not particularly complex and therefore not prone to failure. The auxiliary pull rope may, besides a belt, for example, appear to be particularly suitable for establishing a space-saving and secure connection between the drive unit and the movable mass. Typically, a large number of ropes are designed and available for a wide variety of requirements, also keeping costs limited. In addition, a hydraulic connection may also be conceivable, as well as further mechanical connections—for example by means of a transmission.

Moreover, the drive unit may be configured as a rope drum, allowing for the auxiliary pull rope to be wound up in a particularly space-saving and safe manner. On the one hand, this protects against possible damage and, on the other hand, unwanted contact with other elements, such as the main traction means, can be avoided—especially if a relatively long portion of the auxiliary pull rope has been wound up.

Particularly advantageously, the drive unit may also be configured to always provide sufficient torque to wind up the auxiliary pull rope, thereby further increasing safety since the probability of contact with other elements can be minimized due to the tension in the auxiliary pull rope and also the response behavior can be further improved, in particular due to the lack of play.

According to the invention, a system is further provided, said system comprising a training device and an auxiliary drive for the training device with the features described above, wherein the movable mass may comprise one or more weight plates that may be connected by means of a driver bar and a pin and may be movable in two substantially parallel guide rods, wherein the connection of the movable mass to the main traction means may be established via the driver bar. In this way, the total movable mass may be defined in a particularly simple and reliable manner and safe guidance may also be ensured.

Advantageously, the auxiliary drive of the system may additionally comprise two outer deflection rollers and two rear deflection rollers that may be connected to the movable mass by first and second connecting devices, a first upper clamping device that may be attached to one of the two parallel guide rods with a non-positive connection, and a second upper clamping device that may be attached to the other of the two parallel guide rods with a non-positive connection, wherein the first upper clamping device may accommodate a first end of the auxiliary pull rope, the auxiliary pull rope may be guided through the two outer deflection rollers and through the two rear deflection rollers, and the drive unit may accommodate a second end of the auxiliary pull rope. Thereby, the drive unit may act on the movable mass in such a way that it may be guided in parallel to the two parallel guide rods without a resulting, and thus, braking torque being generated. This reduces the friction and thus the drag and also the wear and therefore allows for an increased precision of the controlled load on the person exercising. According to the invention, the drive unit then only has to apply half of the auxiliary force, F_(Z), acting in total on the movable mass, also allowing for it to be more compact. Of course, the quantities determined have to be adjusted accordingly. In addition to the drive unit that may accommodate the second end of the auxiliary pull rope, the auxiliary drive may further comprise a second drive unit (not shown) that may accommodate the first end of the auxiliary pull rope instead of the first upper clamping device. It may then be possible, depending on the construction type, for example, to control, by means of the control device 2, one of the two drive units very promptly and the other very precisely, allowing for the two to be combined advantageously.

Furthermore, the drive unit may be connected to the movable mass in such a way that the movable mass is connected directly or immediately to a first end of the auxiliary pull rope and the drive unit accommodates a second end of the auxiliary pull rope. This particularly compact design minimizes the susceptibility to errors and the maintenance effort.

DESCRIPTION OF THE DRAWINGS

By way of example, the invention is explained in more detail below with reference to schematic drawings. In the drawings:

FIG. 1 shows a first view of the auxiliary drive,

FIG. 2 shows a first detailed view of the auxiliary drive,

FIG. 3 shows a second view of the auxiliary drive,

FIG. 4 shows a first sectional view of the auxiliary drive,

FIG. 5 shows a third view of the auxiliary drive,

FIG. 6 shows a second detailed view of the auxiliary drive,

FIG. 7 shows a fourth view of the auxiliary drive,

FIG. 8 shows a fifth view of the auxiliary drive,

FIG. 9 shows a third detailed view of the auxiliary drive and

FIG. 10 shows a sixth view of the auxiliary drive.

DETAILED DESCRIPTION

FIG. 1 shows a first view of the auxiliary drive for the training device and a corresponding training device. The auxiliary drive for the training device comprises at least one first force measuring device 1, at least one control device 2 (shown schematically) and at least one drive unit 3. The control device 2 determines a target force, F_(S,max), which is to correspond to the maximum load on the person exercising. This target force, F_(S,max), may be changed both over time and with regard to additionally determined variables; such a change may be continuous, substantially discrete and, in particular, cyclical. The target force, F_(S,max), may be determined, for example, as a function of a direction of movement, a speed of movement, a change in speed of movement, a biometric value of the person exercising or a value of the cardiovascular system of the person exercising, or a combination therefrom; a large number of physiological or biometric values that may be included in the calculation of the target force, F_(S,max), are conceivable. The first force measuring device 1 determines an actual force, F_(S), that is applied to a main traction means 11 of the training device on which the person exercising acts, and that is substantially caused by an acceleration of a movable mass 5 connected to the main traction means. Such a main traction means 11 may, for example, be a rope or a belt, i.e., a machine element which is particularly suitable for transmitting a tractive force. This acceleration of the movable mass 5 comprises both the always-acting acceleration of gravity or acceleration of fall—that is the essentially constant acceleration due to gravity—and an additional dynamic acceleration induced by the person exercising. The actual force, F_(S), determined at the main traction means 11 is transmitted from the first force measuring device 1 to the control device 2. The control device 2 then compares the transmitted actual force, F_(S), with the target force, F_(S,max), and, if the actual force, F_(S), exceeds the target force, F_(S,max), the control device 2 controls the drive unit 3 such that, via a connection of the drive unit 3 to the movable mass 5, an auxiliary force, F_(Z), having a component opposed to the acceleration of gravity acts on the movable mass 5. In FIG. 2, a first detailed view of the auxiliary drive, the connection of the drive unit 3 to the movable mass 5 is shown by way of example as a simple pulley tackle, whereby the auxiliary force, F_(Z), is divided into two halves of equal size.

Since the control device 2 controls the drive unit 3 only when the actual force, F_(S), measured at the main traction means 11 exceeds the target force, F_(S,max), the load on the person exercising can never be greater than the load resulting from the movable mass 5 and the total acceleration acting thereon. If the person exercising does not apply any load resulting in an actual acceleration of the movable mass 5 against the acceleration of gravity, the acceleration of gravity acts as the maximum acceleration of the movable mass 5. Therefore, if at least one component of the auxiliary, F_(Z), acts against the acceleration of gravity, this ensures that the person exercising can never unexpectedly experience a dangerously high load. This protection may also be further increased by limiting the auxiliary force intentionally in absolute terms or relative to the movable mass 5; for example, to a maximum of 150 N or 20% of the movable mass 5. Since, for a fully functioning auxiliary drive for the training device, the auxiliary force, F_(Z), can be limited, the additional load cannot exceed the limited auxiliary force, F_(Z), removed even if a complete system failure is assumed and thus can only be a maximum of 20% of the movable mass 5, for example. In addition to providing increased safety, an increase in power consumption may also be avoided. Since the person exercising may usually only apply a force having a component opposed to the acceleration of gravity to the movable mass 5 via the main traction means 11, the person exercising can only be relieved by the auxiliary force, F_(Z), but never additionally burdened. Only the unexpected absence of the auxiliary force, F_(Z), would mean a correspondingly unexpected load, which in turn would then only be caused by the well-defined movable mass 5 under the influence of the acceleration of gravity.

Thus, the auxiliary drive according to the invention for training devices has an essential safety feature in that, in particular, the maximum possible training load is well defined by the overall movable mass 5. The auxiliary drive according to the invention for training devices offers the particular advantage that the maximum possible training load well defined by the overall movable mass 5 may be reached, but never exceeded. For this purpose, the auxiliary drive according to the invention only ever acts on the total movable mass 5 in such a way that the auxiliary force, F_(Z), acting on the movable mass 5 has at least one component opposed to the acceleration of gravity, i.e. opposed to the acceleration due to gravity or the acceleration of fall. This ensures that, compared to the force acting solely due to the acceleration of gravity via the movable mass 5, the auxiliary force, F_(Z), can only reduce the force to be applied by the person exercising, but never increase it. The auxiliary force, F_(Z), itself can be controlled as finely as desired, which is why the person exercising does not have to accept any discrete increments in mass, for example between individual weight plates.

The safe constraint of the maximum possible training load is also one of the main advantages of the present invention compared to active training devices (fully electric strength training devices) that can generate a dynamic load purely electrically. For such devices, a very high level of safety precautions is necessary in order to avoid excessive loads or even possible injuries in the event of a malfunction. In principle, active training devices (fully electric strength training devices) have a very high cost, both in terms of acquisition and maintenance.

By means of the auxiliary drive according to the invention for the training device, the actual force to be applied, and thus the load on the person exercising, may be adjusted continuously while the exercise is being carried out, while the set maximum training load is guaranteed to be constrained according to the total movable mass 5. In the simplest case, a maximum load which is incremented as finely as needed and which can at most correspond to the maximum training load mechanically predetermined can be set. Such a maximum load can also be adjusted while carrying out an exercise. A purely temporal adjustment or also an adjustment related to a predetermined cycle, which may also take into account cardiovascular or biometric values of the person exercising, is conceivable here.

As shown by way of example in FIG. 1, the auxiliary drive according to the invention may be configured as a conversion kit such that only additional elements are mounted on an existing strength training device, but no changes have to be made to the existing mechanics or to a cover or force-transmitting parts of the existing strength training device. There is also no need to deinstall any pulling ropes or weight plates and there is no need for specialist personnel trained in the use of electrics or electronics in order to put the device into operation and monitor it during normal operation. Due to the type of mounting and the basic functionality of the auxiliary drive according to the invention, as described above, the person exercising cannot experience higher mechanical loads than the settable maximum training load, the range of which is already specified by the manufacturer via the weight plates. In this way, problems with product liability or outstanding guarantee claims can also be avoided.

Moreover, such an auxiliary drive for the training device may also provide an emergency braking function for the drive unit 3. In the event of a power failure or another malfunction, a hardware-implemented safety emergency stop function may be integrated, which then short-circuits the windings of an electric motor of the drive unit 3. As a result, the movable mass 5 can be braked with a maximum torque of the electric motor in the event of a fault or in the event of disproportionately deviating measured values, for example exceeding a limit value.

When, in the auxiliary drive, the control device 2 compares the actual force, F_(S), transmitted thereto with the target force, F_(S,max), and determines that the actual force, F_(S), exceeds the target force, F_(S,max), the control device 2 advantageously controls the drive unit 3 in such a way that, via the connection of the drive unit 3 to the movable mass 5, the auxiliary force, F_(Z), reduces the determined actual force, F_(S), applied to the main traction means 11. As a result, it can be ensured verifiably, namely by means of the first force measuring device 1, that the actual force, F_(S), applied to the main traction means 11 has actually been reduced by the auxiliary force, F_(Z), whereby the safety can be increased. The auxiliary drive may therefore verify whether the auxiliary force, F_(Z), actually reduces the actual force, F_(S), applied to the main traction means 11 or whether the applied auxiliary force, F_(Z), noticeably reduces the actual force, F_(S), applied to the main traction means 11.

When, in the auxiliary drive, the control device 2 compares the actual force, F_(S), transmitted thereto with the target force, F_(S,max), and determines that the actual force, F_(S), exceeds the target force, F_(S,max), the control device 2 advantageously controls the drive unit 3 in such a way that, via the connection of the drive unit 3 to the movable mass 5, the auxiliary force, F_(Z), reduces the determined actual force, F_(S), applied to the main traction means 11 substantially to the target force, F_(S,max). This makes it possible to ensure verifiably that the force to be applied by the person exercising substantially corresponds to the target force, F_(S,max), existing friction losses or measurement inaccuracies notwithstanding, for example. When the target force, F_(S,max), changes, the actual force, F_(S), changes accordingly due to the control, since the auxiliary force, F_(Z), is continuously adjusted. While retaining all of the positive safety features described above, a load that can be adjusted and optimized almost at will can be generated for the person exercising. It is also possible to detect losses inherent to the system, such as friction losses, and to adapt the control accordingly.

The auxiliary drive may advantageously additionally comprise a movement sensor 8 (not shown) configured to determine a direction of movement of the movable mass 5 and to transmit it to the control device 2. The control device 2 may further be configured to additionally determine the target force, F_(S,max), as a function of the direction of movement of the movable mass 5. Thereby, for example, the “eccentric overload” described above can be generated, allowing for an improved muscle formation can be achieved since the load to be exerted by the person exercising can be adapted to the current direction of movement in an advantageous manner. The muscles of the person exercising can be loaded up to 30% more in the eccentric contraction than in the concentric contraction, whereby the desired training stimulus is applied to the muscles by means of a correspondingly adjusted target force, F_(S,max), and a correspondingly changed auxiliary force, F_(Z), so that a correspondingly increased muscle growth is triggered.

The movement sensor 8 may advantageously be integrated directly into the drive unit, ensuring both a particularly space-saving configuration and special protection against possible external damage. Furthermore, the integrity of the measurement can be increased if the movement sensor 8 carries out the measurement directly in the drive unit 3, so that no other machine elements are involved that could distort the measurement, for example because they may oscillate or have play.

Furthermore, the first force measuring device 1 of the auxiliary drive may be configured to determine a tension of the main traction means 11 in order to determine the actual force, F_(S). In principle, with the tension known, the actual force, F_(S), applied can be inferred very precisely, also increasing the precision of the control resulting from the comparison with the target force, F_(S,max). As described above, the control of the drive unit 3 by the control device 2 is essentially based on the comparison of the actual force, F_(S), transmitted by the first force measuring device 1 with the target force, F_(S,max). Consequently, the increased precision of the determination of the actual force, F_(S), also results in a possibility to more precisely control the drive unit 3.

The first force measuring device 1 may advantageously be configured in such a way that the tension of the main traction means 11 is determined by means of a deflection; see also FIG. 1. This represents a particularly reliable method of determining the tension and therefore determining the applied actual force, F_(S), in turn allowing the reliability of the control of the drive unit 3 resulting from the comparison with the target force, F_(S,max), by means of the control device 2 to be increased. As shown by way of example in FIG. 1, the first force measuring device 1 may have a spring mechanism, the deflection of which is the greater, the greater the tension present in the main traction means 11 is. Hence, the actual force, F_(S), can be determined from the deflection of the spring mechanism.

Moreover, the first force measuring device 1 may also be configured to determine an elongation of the main traction means 11 in order to determine the actual force, F_(S). The applied actual force, F_(S), may also be inferred very precisely from an elongation.

Since, in the linear-elastic range (proportional range, “Hooke's straight line”), the elongation is proportional to the tensile stress and Hooke's law therefore applies, both types of determination of the actual force, F_(S), may be carried out either alternatively or in parallel. If there are two measured values of the actual force, F_(S), determined in different ways, they can be compared with one another in a suitable manner, whereby the integrity of the measurement can be increased further. An assessment of the suitability of the measurement method with regard to the speed of the change in the measured values or the dynamics in general is also conceivable. The comparison of the values of the actual force, F_(S), determined via tension and elongation may therefore take the respective values directly into account, but weighting may also (additionally) be performed based on a change in the underlying values.

The first force measuring device 1 may advantageously comprise a strain gauge, DMS, and/or a magnetostrictive sensor operating according to the principle of magnetostriction. Both strain gauges and magnetostrictive sensors are available from common suppliers in a wide variety of designs well adapted to the respective needs, also allowing for costs to be reduced. Again, the determined quantities may be compared with one another directly or in terms of their respective change. In addition, strain gauges, in particular, are very space-saving and can also be easily placed in places difficult to access.

Furthermore, the first force measuring device 1 may be configured to determine the actual force, F_(S), by comprising a weighing device (not shown) which can be configured to determine the mass of the movable mass 5 and by further comprising an acceleration sensor (not shown) configured to determine a second change of a position of the movable mass 5 over time. Given knowledge of the accelerated mass, in particular the accelerated movable mass 5, and knowledge of the corresponding acceleration, the actual force, F_(S), can be determined directly from Newton's second law by simply multiplying the two determined values. For this purpose, the weighing device must, at a point at which it can be recognized that the movable mass rests, measure a difference between a weight force for the case that the movable mass only rests due to the influence of acceleration of gravity and for the case that the movable mass does not rest. The advantage here is that the weighing device only has to determine the difference described above and that it is therefore irrelevant whether other masses are also weighed at the same time, respectively. For example, it is also possible to mount the weighing device under a mass plate stack comprising a number of mass plates, from which only, for example, the top two mass plates are then lifted off. As already described above, several options of determining the actual force, F_(S), can be carried out both alternatively and in parallel. If two or more measured values of the actual force, F_(S), determined in different ways are available, they can be compared with one another in a suitable manner, whereby the integrity of the measurement can be further increased. In general, the present invention regards it as extremely advantageous if—quite generally—determined variables are determined in different ways and/or multiple times; in particular, the sensor data fusion may be used for this purpose. As mentioned above, the dynamics of the underlying movement may be of importance in the sensor data fusion, as may be the dynamics of the determined values.

Advantageously, the acceleration sensor may be a movement sensor configured to determine the absolute or relative position of the movable mass 5 and the first and second time derivative thereof or a variable correspondingly proportional thereto. It is conceivable that both the above-described movement sensor 8 is used in the configuration described here and that an additional movement sensor is used, the data of which may then be used in addition to those of the existing movement sensor 8 and also to determine further measured values therefrom, in particular after the sensor data fusion has taken place. If the movement sensor 8 described above can determine the acceleration of the moving mass 5, it is therefore sufficient that the first force measuring device 1 comprises the weighing device described above in order to then determine the actual force, F_(S), applied to the main traction means 11 from the values determined by the movement sensor 8 and the weighing device. Alternatively, the acceleration determined by the additional movement sensor may again be compared with the acceleration determined by the movement sensor 8, and thus, for example, the integrity of the measurement can be improved.

In the auxiliary drive, the connection of the drive unit 3 to the movable mass 5 may also act at a first point of the main traction means 11 that is closer to the movable mass 5 than a second point of the main traction means 11, at which the first force measuring device 1 determines the actual Force, F_(S). This ensures that, in the course of the force flow within the main traction means 11, there can be no distortion of the actual force, F_(S), that is determined by the first force measuring device 1, is applied to the main traction means 11 of the training device and is essentially to be applied by the person exercising. When the drive unit 3 acts, according to the invention, at the first point of the main traction means 11, a particularly compact design of the auxiliary drive can be obtained.

In addition, the drive unit 3 may comprise a generator (not shown), making it possible, especially in the case of the eccentric movement, that not only no energy is consumed, but energy can even be recuperated, since the generator, for example, provides the braking torque required to generate the appropriate auxiliary force, F_(Z). Since the energy consumption of the drive unit 3 is reduced in this way and additional energy is generated by the generator, any batteries/accumulators that may be present may also be designed smaller and cheaper or may be used correspondingly longer. If there are no batteries/accumulators present, the generator will in any case reduce the power consumption and thus also the costs; environmental protection is also boosted.

Advantageously, the auxiliary drive may additionally comprise a second force measuring device (not shown) configured to determine the auxiliary force, F_(Z), acting on the movable mass 5 and/or to determine the work effectively performed by the drive unit 3. As a result, the control of the drive unit 3 may be verified, the control precision may be increased, and the error detection may be improved. An oscillation may also be prevented better in areas in which it might unintentionally be caused by the control. Again, the second force measuring device may be integrated into the drive unit 3, allowing for a compact, protected design, increasing the integrity of the measurement and allowing for a comparatively simple force-displacement determination for effectively determining the work done therefrom. The second force measuring device, like the first force measuring device, may also comprise a magnetostrictive sensor. In addition to the work effectively done, the power actually generated currently by the drive unit 3 may also be determined. In principle, additionally or alternatively, the corresponding quantities may also be determined taking into account a determined torque.

Furthermore, the auxiliary drive may additionally comprise an operating unit 4 (shown schematically) configured to transmit data from which the control device 2 may additionally determine the target force, F_(S,max), to the control device 2. A large number of configurations are conceivable here. In principle, the operating unit 4 may be configured to specify the target force, F_(S,max), and in particular also the curve or, typically, change over time thereof. For example, it is possible to choose from a number of different training programs from which the respectively valid target force, F_(S,max), is then determined. A comparatively simple control device 2 may also be used here, which, in addition to the curves of the target force, F_(S,max), obtained from the operating unit 4, does not, or only to a small extent, perform further calculations in order to determine the target force, F_(S,max). Consequently, a fundamentally modular structure is also conceivable, expressly also providing redundancies, that is to say different units may carry out the same or similar calculations. This further increases the flexibility and the range of applications of the auxiliary drive.

In addition, the control device 2 may further be configured to transmit data to the operating unit 4 and/or to an IT infrastructure and to receive data from the IT infrastructure. The operating unit 4 may further be configured to receive data from an external measuring unit and/or to receive/transmit data from/to the IT infrastructure. This makes it possible, for example, to show the person exercising how to best follow target curves or how the person exercising has followed them. Furthermore, results, for example the number of cycles or the work done by the trainee or current quantities such as the currently generated power, may be transmitted to the operating unit 4 in order to provide information and to ensure a verification of a selected target. Moreover, the data may be transferred to the IT infrastructure, such as a computer or a cloud, for analysis and evaluation. In particular, the development of the person exercising over time may thus be well represented and verified and useful adjustments may be made, if necessary. Advantageously, statically or dynamically determined quantities of the person exercising may be transmitted via the operating unit, either by input or by forwarding data, to the control device 2 or the corresponding calculations may be carried out in the operating unit 4 itself. In addition to, for example, height, weight, age, gender of the person exercising, other biometric values or (current) cardiovascular values suitable for determining a corresponding training plan are also conceivable here. The specification for the target force curves, F_(S,max), ultimately generated may also originate from a (possibly second) IT infrastructure, such as a second computer or a second cloud. They may also be generated in the operating unit 4 itself or even in the control device 2. The adjustment of the target force, F_(S,max), may also proceed continuously: for example, the IT infrastructure may obtain the cardiovascular values determined by the operating unit 4 together with the data that the control device 2 transmits to the operating unit 4. The IT infrastructure may then in turn carry out a corresponding adjustment of the target force, F_(S,max), and transmit it to the control device 2 via the operating unit 4. Restrictions to a single specific structure are therefore unnecessary. The fundamental redundancy of determining and specifying the target force, F_(S,max), may be viewed as particularly advantageous since different units may be particularly suitable depending on the (current) data availability and computing power. Via a (radio) network connection, it is also possible, in particular, for data and curves to be transmitted and analyzed without an operator being physically at the location of the auxiliary drive. In this way, it is also possible for a respective person exercising to find an individually adapted training program on various auxiliary drives according to the invention and training results of the person exercising may in turn be recorded and evaluated centrally.

A control device 2 as used herein refers to any device with a processor, memory and a storage device that may execute instructions including, but not limited to, personal computers, server computers, computing tablets, set top boxes, video game systems, personal video recorders, telephones, personal digital assistants (PDAs), portable computers, and laptop computers. These computing devices may run an operating system, including, for example, variations of the Linux, Microsoft Windows, Symbian, and Apple Mac operating systems. The techniques may be implemented with machine readable storage media in a storage device included with or otherwise coupled or attached to a computing device. That is, the software may be stored in electronic, machine readable media. These storage media include, for example, magnetic media such as hard disks, optical media such as compact disks (CD-ROM and CD-RW) and digital versatile disks (DVD and DVD±RW); flash memory cards; and other storage media. As used herein, a storage device is a device that allows for reading and/or writing to a storage medium. Storage devices include hard disk drives, DVD drives, flash memory devices, and others. The control device 2 may incorporate a transceiver to communicate remotely with external processors/users, and the operating unit 4 may be hard wired or remotely in communication with the drive unit 3, as shown in FIG. 1.

Advantageously, the auxiliary drive may further comprise an auxiliary pull rope 12 connected to both the drive unit 3 and the movable mass 5 indirectly, as shown in FIG. 1, or directly, as shown in FIG. 10, thus establishing the connection of the drive unit 3 to the movable mass 5. The direct connection shown in FIG. 10 may be regarded as not particularly complex and therefore not prone to failure. The auxiliary pull rope 12 may, besides a belt, for example, appear to be particularly suitable for establishing a space-saving and secure connection between the drive unit 3 and the movable mass 5. Typically, a large number of ropes are designed and available for a wide variety of requirements, also keeping costs limited. In addition, a hydraulic connection between the drive unit 3 and the movable mass 5 would also be conceivable, as well as other mechanical connections—for example by means of a transmission, which may also include a slipping clutch.

In addition, the drive unit 3 may be configured as a rope drum, see FIG. 1, allowing for the auxiliary pull rope 12 to be wound up in a particularly space-saving and safe manner. On the one hand, this protects against possible damage and, on the other hand, undesired contact with other elements, such as the main traction means 11, can be avoided—particularly if a relatively long portion of the auxiliary pull rope 12 has been wound up. A possible risk of injury to the person exercising or other people may also be minimized in this way. In addition, the rope drum may have anti-trap protection (not shown).

Particularly advantageously, the drive unit 3 may also be configured to always provide sufficient torque for winding up the auxiliary pull rope 12, allowing for safety to be increased further since, due to the tension present in the auxiliary pull rope 12, the probability of contact with other elements can be minimized and furthermore, the response behavior can be further improved, in particular due to the lack of play.

Furthermore, a system according to the invention may comprise the training device and the auxiliary drive for the training device with the features described above, wherein the movable mass 5 comprises one or more weight plates that are connected by means of a driver bar 6 a and a pin 6 b and are substantially movable in two parallel guide rods 7 a and 7 b, the connection of the movable mass 5 to the main traction means 12 being established via the driving bar 6 a. The overall movable mass 5 can thus be defined in a particularly simple and reliable manner and safe guidance thereof can also be ensured. Since the driver bar 6 a usually rests on the top mass plate with an area which is wider than the diameter of a cross section of the driver bar 6 a guided in the mass plate, the driver bar 6 a ensures, along with the pin 6 b, that the movable mass 5 is held together even if a plurality of weight plates or mass plates are included.

FIG. 3 shows a second view of the auxiliary drive. Advantageously, cf. FIGS. 1 to 3, the auxiliary drive of the system may additionally comprise two outer deflection rollers 19 a and 19 b and two rear deflection rollers 20 a and 20 b, which are connected to the movable mass 5 by a first and a second connecting device 13 a and 13 b, and also a first upper clamping device 10 a attached to one of the two parallel guide rods 7 a with a non-positive connection and a second upper clamping device 10 b attached to the other of the two parallel guide rods 7 b with a non-positive connection, wherein the first upper clamping device 10 a may accommodate a first end of the auxiliary pull rope 12, the auxiliary pull rope 12 may be guided through the two outer deflection rollers 19 a and 19 b and through the two rear deflection rollers 20 a and 20 b, and the drive unit 3 may accommodate a second end of the auxiliary pull rope 12. Thereby, the system may be configured in such a way that the drive unit 3 acts on the movable mass 5 by means of the auxiliary force, F_(Z), in such a way that it the movable mass 5 guided in parallel to the two parallel guide rods 7 a and 7 b without a resulting, and thus, braking torque being generated. This reduces the friction and thus the drag and also the wear and therefore allows for an increased precision of the controlled load on the person exercising. FIG. 4 shows a first sectional view of the auxiliary drive along the line K-K of FIG. 3. As shown in FIG. 4, in order to prevent the undesired moment, substantially vertical portions of the main traction means 11, the auxiliary pull rope 12 and both central axes of the two parallel guide rods 7 a and 7 b lie substantially in one plane. According to the invention, in the case of the simple pulley tackle shown, the drive unit 3 only has to apply half of the total auxiliary force, F_(Z), acting on the movable mass 5, also allowing for it to be more compact. Of course, the quantities determined or specified are to be adapted accordingly. In addition to the drive unit 3 accommodating the second end of the auxiliary pull rope 12 described above, the auxiliary drive may further comprise a second drive unit (not shown) which, instead of the first upper clamping device 10 a, accommodates the first end of the auxiliary pull rope 12. It may then be possible due to the configuration, for example, to control, by means of the control device 2, one of the two drive units very promptly and to control the other very precisely, allowing for the two to be combined advantageously.

As shown in FIG. 2, the second connecting device 13 b with a second sliding bushing 14 b, which in turn is firmly connected to the movable mass 5, may be configured as a second lower clamping device; in the area of the first guide rod 7 a, the auxiliary drive accordingly comprises a first connecting device 13 a connected to a first sliding bushing 14 a, which in turn is firmly connected to the movable mass 5, as a first lower clamping device. One or more screw connections may be provided for fastening each of the two lower clamping devices and the two upper clamping devices 10 a and 10 b. The clamping devices may be implemented in one or more parts. A two-part embodiment with two screw connections each allows for a particularly simple mounting both on the sliding bushings 14 a and 14 b (see FIG. 4) and on the two parallel guide rods 7 a and 7 b. The (partial) release of one of the screw connections is usually suitable for adjusting both a rotational and a translational degree of freedom. Fine adjustment may therefore be carried out very quickly. The two outer deflection rollers 19 a and 19 b and the two rear deflection rollers 20 a and 20 b each deflect the auxiliary pull rope 12 substantially by 90°.

FIGS. 5 and 6 show that the first and the second connection device 13 a and 13 b may also be connected to one another via one third connection device 13 c each. The connection of all the connection devices mentioned to the movable mass 5 is established by means of a securing bolt 6 c in each of the two third connection devices 13 c. Since the two lower clamping devices may be omitted here, no negative influence whatsoever can be exerted on the sliding bushings 14 a and 14 b which could possibly result in increased friction between the sliding bushings 14 a and 14 b and the two parallel guide rods 7 a and 7 b.

FIGS. 7 to 9 show that alternatively the first and the second connection device 13 a and 13 b may also be connected directly to the uppermost mass plate and thus to the movable mass 5 by means of a first and a second fastening belt 9 a and 9 b. Particularly advantageously, a center line of the respective fastening belt 9 a or 9 b and the corresponding vertical portion of the auxiliary pull rope 12 are each substantially in one plane. In this way, it can be avoided that a torque acting on the first or the second connecting device 13 a and 13 b is generated via the two outer deflection rollers 19 a and 19 b. Advantageously, the first and the second fastening belt 9 a and 9 b may each be tensioned via a first and a second tensioning device 15 a and 15 b. This allows for quick tool-free assembly of the first and second connecting devices 13 a and 13 b with the uppermost mass plate.

As shown in FIG. 10, the connection of the drive unit 3 to the movable mass 5 may be established such that the movable mass 5 is directly connected to a first end of the auxiliary pull rope 12 and the drive unit 3 accommodates a second end of the auxiliary pull rope 12. This particularly compact configuration minimizes the susceptibility to errors and the maintenance effort. In addition, the rope length of the auxiliary pull rope 12 can be roughly halved, assuming the same lifting height of the movable mass 5, since the simple pulley tackle is omitted. If a lower torque of the drive unit 3 is desired or required, a multiplied pulley tackle (not shown) may of course also be used to establish the connection between the drive unit 3 and the movable mass 5.

Of course, the individual features of the invention are not restricted to the combinations of features described within the scope of the exemplary embodiments presented and may also be used in other combinations, depending on predetermined parameters.

-   -   1: First force measuring device     -   2: Control device     -   3: Drive unit     -   4: Operating unit     -   5: Movable mass     -   6 a: Driver bar     -   6 b: Pin     -   6 c: Securing bolt     -   7 a, 7 b: Guide rod     -   8: Movement sensor     -   9 a, 9 b: Fastening belt     -   10 a, 10 b: Upper clamping device     -   11 Main traction means     -   12: Auxiliary pull rope     -   13 a, 13 b, 13 c: Connecting device     -   14 a, 14 b: Sliding bushing     -   15 a, 15 b: Tensioning device     -   19 a, 19 b: Outer roller     -   20 a, 20 b: Rear roller 

It is claimed:
 1. An auxiliary drive for a training device, comprising a first force measuring device (1), a control device (2), and a drive unit (3), wherein said control device (2) is configured to determine a target force (F_(S,max)), said first force measuring device (1) is configured to determine an actual force (F_(S)) that is applied to a main traction means (11) and is substantially caused by an acceleration of a movable mass (5) connected to said main traction means (11), and wherein said first force measuring device (1) is further configured to transmit the determined actual force (F_(S)) to said control device (2), said control device (2) is further configured to compare the actual force (F_(S)) with the target force (F_(S,max)) and to control said drive unit (3) in such a way that, if the actual force (F_(S)) exceeds the target force (F_(S,max)), an auxiliary force (F_(Z)) having a component opposite to an acceleration of gravity acts on said movable mass (5) through a connection of said drive unit (3) to said movable mass (5).
 2. The auxiliary drive according to claim 1, wherein said control device (2) is further configured to control said drive unit (3) in such a way that, if the actual force (F_(S)) exceeds the target force (F_(S,max)), the auxiliary force (F_(Z)) reduces the actual force (F_(S)) applied and determined on said main traction means (11).
 3. The auxiliary drive according to claim 1, wherein said control device (2) is further configured to control said drive unit (3) in such a way that, if the actual force (F_(S)) exceeds the target force (F_(S,max)), the auxiliary force (F_(Z)) reduces the actual force (F_(S)) applied and determined on said main traction means (11) substantially to the target force (F_(S,max)).
 4. The auxiliary drive according to at least one of claim 1, wherein said auxiliary drive additionally comprises a movement sensor (8) configured to determine a direction of movement of said movable mass (5) and to transmit it to said control device (2), and said control device (2) is further configured to additionally determine the target force (F_(S,max)) as a function of the direction of movement of said movable mass (5).
 5. The auxiliary drive according to claim 4, wherein said movement sensor (8) is configured to determine an absolute or relative position of said movable mass (5) and/or the first and/or second time derivative thereof or a correspondingly proportional variable, respectively, and to transmit it to said control device (2), and said control device (2) is further configured to additionally determine the target force (F_(S),max) as a function of the position of said movable mass (5) and/or the first and/or second time derivative thereof.
 6. The auxiliary drive according to at least one of claim 4, wherein said movement sensor (8) is integrated into said drive unit (3).
 7. The auxiliary drive according to at least one of claim 1, wherein said first force measuring device (1) is configured to determine a tension of said main traction means (11) in order to determine the actual force (F_(S)).
 8. The auxiliary drive according to claim 7, wherein said first force measuring device (1) is configured to determine the tension of said main traction means (11) by means of a deflection.
 9. The auxiliary drive according to at least one of claim 1, wherein said first force measuring device (1) is configured to determine an elongation of said main traction means (11) in order to determine the actual force (F_(S)).
 10. The auxiliary drive according to claim 9, wherein said first force measuring device (1) comprises a strain gauge and/or a magnetostrictive sensor.
 11. The auxiliary drive according to at least one of claim 1, wherein said first force measuring device (1) is configured to determine the actual force (F_(S)) in that it comprises a weighing device configured to determine the mass of said movable mass (5) and in that it further comprises an acceleration sensor configured to determine a second change of a position of said movable mass (5) over time.
 12. The auxiliary drive according to claim 11, wherein said acceleration sensor is a movement sensor (8) configured to determine the absolute or relative position of said movable mass (5) and the first and second time derivative thereof or a respective quantity correspondingly proportional thereto.
 13. The auxiliary drive according to at least one of claim 1, wherein the connection of said drive unit (3) with said movable mass (5) acts at a first point of said main traction means (11) closer to said movable mass (5) than a second point of said main traction means (11) at which said first force measuring device (1) determines the actual force (F_(S)).
 14. The auxiliary drive according to at least one of claim 1, wherein said drive unit (3) comprises a generator.
 15. The auxiliary drive according to at least one of claim 1, wherein the auxiliary drive further comprises a second force measuring device configured to determine the auxiliary force (F_(Z)) acting on said movable mass (5).
 16. The auxiliary drive according to at least one of claim 1, wherein said auxiliary drive further comprises an operating unit (4), and said operating unit (4) is configured to transmit data, from which said control device (2) additionally determines the target force (F_(S,max)), to said control device (2).
 17. The auxiliary drive according to claim 16, wherein said control device (2) is further configured to transmit data to said operating unit (4) and/or to an IT infrastructure and to receive data from the IT infrastructure and said operating unit (4) is further configured to receive data of an external measuring unit and/or from the IT infrastructure and/or to transmit data to the IT infrastructure.
 18. The auxiliary drive according to at least one of claim 1, said auxiliary drive further comprising an auxiliary pull rope (12) connected to said drive unit (3) and said movable mass (5) and thus establishing the connection of said drive unit (3) to said movable mass (5).
 19. The auxiliary drive according to claim 18, wherein said drive unit (3) is configured as a rope drum.
 20. The auxiliary drive according to claim 19, wherein said drive unit (3) is configured to always provide a sufficient torque for winding up said auxiliary pull rope (12).
 21. A system comprising the training device and the auxiliary drive for the training device according to claim 18, wherein said movable mass (5) comprises one or more weight plates which are connected by means of a driver bar (6 a) and a pin (6 b) and are movable in two parallel guide rods (7 a, 7 b), and the connection of said movable mass (5) with said main traction means (11) is established via said driver bar (6 a).
 22. The system according to claim 21, wherein said auxiliary drive additionally comprises two outer deflection rollers (19 a, 19 b) and two rear deflection rollers (20 a, 20 b) which are connected to said movable mass (5) by a first and a second connecting device (13 a, 13 b), a first upper clamping device (10 a) attached to one of said two parallel guide rods (7 a, 7 b) with a non-positive connection and a second upper clamping device (10 b) attached to the other of said two parallel guide rods (7 a, 7 b) with a non-positive connection, wherein said first upper clamping device (10 a) accommodates a first end of said auxiliary pull rope (12), said auxiliary pull rope (12) is guided through the two outer deflection rollers (19 a, 19 b) and through the two rear deflection rollers (20 a, 20 b), and said drive unit (3) accommodates a second end of said auxiliary pull rope (12).
 23. The system according to claim 21, wherein the connection of said drive unit (3) to the movable mass (5) is established in that said movable mass (5) is connected to a first end of said auxiliary pull rope (12) and said drive unit (3) accommodates a second end of said auxiliary pull rope (12). 